212 Additional Remarks on the State in which 
in wines might be estimated by submitting them to a care- 
ful distillation, and by ascertaining the specific gravity of 
the distilled liquor with the precautions which [ have for- 
merly described. 
This conclusion may be objected to, by supposing that 
the lowest temperature, at which the distillations were 
performed, was sufficient for the formation of alcohol from 
the elements” existing in the wine; but it is nut easy to 
conceive how this should happen, without some of those 
other changes which I have just noticed. 
It has been stated, in my former paper, that the separa- 
tion of alcohol from wine, by the addition of subcarbonate 
of potash, is prevented by the combination of the alkaline 
salt with the colouring-extractive, and acid contained in 
the liquor. I have also shortly noticed some unsuccessful 
attempts to separate these substances by other means than 
distillation. 
In prosecuting the inquiry, this difficnity has been sur- 
mounted, and I shall proceed to show that alcoho] may be 
separated from wine without the intervention of heat, and 
that the proportion thus afforded is equal to that yielded by 
distillation. 
When the acetate *, or subacetatet of lead, or the sub- 
nitrate of tin f are added to wine, a dense insoluble preci- 
pitate is quickly formed, consisting of a combination of the 
metallic oxide with ihe! acid and colouring-extractive mat- 
ter of the wine ; and when this is separated by filtration, a 
colourless fluid is obtained, containing alcohol, water, atid 
a portion of the acid of the metallic salt, provided the latter 
has not been added in excess, in which case a part remains 
undecomposed, 
The acetate of Jead and the subnitrate of tin produce the 
desired effect of separating the colouring and acid matters, 
in the greater number of instances ; but they are less rapid 
and perfect in their action, and not so generally applicable 
as the subacetate of lead §, which is the substance that I 
commonly employed. 
The following experiment was made with a view to as- 
certain the effect of this salt. 
* Sugar of lead. 
+ Formed by boiling two parts of sugar of lead with one of finely pow- 
dered litharge, in six parts cf water. The solution should be preserved in 
well closed phials, as it is rapidly decomposed by attracting carbonic acid 
from the atmosphere. Even while hot, a portion of carbonate of lead is 
formed in it. 
¢ Prepared by dissolving protoxide of tin in cold dilute nitric ache: 
§ The effect of this salt upon colouring matter was first POeS out to 
me by Mr. E.M. Noble, of Chelsea. 
Twenty 
i 
